I think you are wrong when you say that rockstar made their games for money. When they started with Lemmings, it became a legendary game, and they do they job properly, you hardly find any bugs in their games, at least compared to something like EA. Not to mention that the content in their games is pretty fun, you can always find something new. But they just might aswell leave the multiplayer part for the MTA team, with some code already written to help, like they did in SA (or so i presumed after reading stuff).